1. Technical Field
The present invention relates to a cartridge that is mounted to a liquid jetting apparatus to supply a liquid, and a method for supplying a liquid.
2. Related Art
A cartridge that is mounted to a printer to supply ink is described in JP-A-2009-226809. The cartridge of JP-A-2009-226809 includes a case, an ink pack stored in the case, a flat plate attached to the ink pack, and a spring for biasing this flat plate. The ink pack includes a flexible storing bag for storing ink, and an ink supply tube for supplying the ink in the storing bag to the outside. The flat plate is attached to the storing bag. The spring is arranged between the flat plate and a bottom plate of the case, and presses the ink pack against the ceiling plate of the case via the flat plate. Accordingly, the storing bag is flattened between the flat plate and the ceiling plate, and thus the ink in the ink pack is supplied to the printer side via the ink supply tube.
In the cartridge of JP-A-2009-226809, the thickness of the ink pack in the vertical direction decreases as the amount of ink decreases. Here, when the thickness of the ink pack decreases, the spring extends by the reduced thickness, and thus biasing force of the spring upwardly biasing the flat plate is weakened. Therefore, there is a problem in that in the cartridge of JP-A-2009-226809, pressure for supplying the ink to the printer decreases as the amount of the ink decreases, and the supply thereof becomes instable.